Nimble not updating my credit report

I had a wonga loan which was erroneously sold to nimble last year because i had settled it months before it was sold to them by wonga, i was harrased by nimble over and over and i kept telling them the loan was settled, i eventually sent them a paid up letter and they finally removed the loan from their system but they did not remove the loan from the credit bereau and i checked my credit score again yesterday and this loan is still on my credit score and it says its in arrears, why must is nimble do this to me, when i called yesterday, the consultants line was really bad and i asked him to call me back and he did not and they do this all the time, when i call to query they say they will get back to me immediately and THEY NEVER DO!!! Nimble needs to sort this out asap